FUNCTION: [Summary is not available for the mouse gene. This summary is for the human ortholog.] This gene encodes a member of the heparan sulfate/heparin GlcNAc N-deacetylase/ N-sulfotransferase family. The encoded enzyme is a type II transmembrane protein that resides in the Golgi apparatus. This monomeric bifunctional enzyme catalyzes the N-deacetylation and N-sulfation of N-acetylglucosamine residues in heparan sulfate and heparin, which are the initial chemical modifications required for the biosynthesis of the functional oligosaccharide sequences that define the specific ligand binding activities of heparan sulfate and heparin. [provided by RefSeq, Nov 2008] PHENOTYPE: Mice homozygous for a knockout allele exhibit decreased anxiety-related behavior, cholesterol levels and CD8+ T cells due to moderate heparan-sulfate undersulfation. [provided by MGI curators]